1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) device, and more particularly, to an LCD device with a sensing electrode for sensing a user's touch.
2. Discussion of the Related Art
A liquid crystal display (LCD) device is widely applied in various fields, for example, notebook computers, monitors, spacecraft, and aircraft, due to advantageous properties such as low driving voltage, low power consumption, and portability. An LCD device includes a lower substrate, an upper substrate, and a liquid crystal layer disposed between the lower and upper substrates. According to whether or not an electric field is applied, an alignment of the liquid crystal layer is controlled so that light transmittance is controlled in the LCD device, thereby displaying images on the LCD device.
Typically, a mouse or keyboard is used as an input device for an LCD device. However, when the LCD device is applied to navigation systems, mobile terminals, and electric appliances, a touch screen is recently used as a new input means instead of using the mouse or keyboard, wherein the touch screen enables a user to directly input information with a finger or pen.
Hereinafter, a related art LCD device with a touch screen will be described in detail as follows. FIG. 1 is a cross section view illustrating a related art LCD device.
As shown in FIG. 1, the related art LCD device includes a liquid crystal panel 10 and a touch screen 20. The liquid crystal panel 10 displays images. Here, the liquid crystal panel 10 includes a lower substrate 12, an upper substrate 14, and a liquid crystal layer 16 formed between the lower and upper substrates 12 and 14. The touch screen 20 is formed on an upper surface of the liquid crystal panel 10, and the touch screen 20 is provided to sense a user's touch. The touch screen 20 includes a touch substrate 22, a first sensing electrode 24 formed on a lower surface of the touch substrate 22, and a second sensing electrode 26 formed on an upper surface of the touch substrate 22.
The first sensing electrode 24 is arranged in the horizontal direction on the lower surface of the touch substrate 22; and the second sensing electrode 26 is arranged in the vertical direction on the upper surface of the touch substrate 22. Thus, if the user touches a predetermined portion, capacitance between the first and second sensing electrodes 24 and 26 is changed at the touched portion. As such, the user's touching point is sensed by the change of the capacitance.
However, since the related art LCD device is formed with the touch screen 20 additionally formed on the upper surface of the liquid crystal panel 10, the entire thickness is increased due to the touch screen 20, the manufacturing process is complicated, and the manufacturing cost is also increased.